change error-code to errorCode for compatibility

Author: Ole Lensmar

guidelines/sample-server/files/models.json

@@ -86,7 +86,7 @@
     "description": "A shared model for error message",
     "required" : ["error-code","reason"],
     "properties": {
-      "error-code": {
+      "errorCode": {
         "type": "integer",
         "format": "int64"
       },